Rain is a good sign for gypsy moth population control

FALL RIVER — After last summer’s drought, this summer is proving to be one with an abundance of gypsy moth caterpillars, but there is hope the crawling critters won’t have the same presence next year.

By now, you’ve likely noticed the caterpillars climbing along your house. Or heard the sound of caterpillar waste dropping from leaves up above, never mind the disappearing foliage.

As of right now, most of the damage is done, said Joseph Elkinton, a professor in the UMass Amherst Department of Environmental Conservation.

“It’s too late to do anything now,” he said.

Elkinton said the best time to take action against gypsy moths is in early May while they are caterpillars before they start eating leaves, causing damage to trees.

However, a Japanese “fungus disease” called entomophaga maimaiga helps keep the gypsy moth population manageable.

The 2016 drought sparked the gypsy moth outbreak happening now according to Elkinton, but rain powers the fungus to produce and spread, limiting gypsy moth populations. The lack of rain last year allowed gypsy moth populations to multiply.

Elkinton said he is hopeful this year’s rain and entomophaga maimaiga fungus will “wipe out the problem and make it a non-problem” and “drive the system to low density again.”

Though some arborists may recommend continuing to protect trees with the use of pesticides, Elkinton said it would ultimately be ineffective.

The moths mate in August and lay eggs in trees, under lawn furniture and embed themselves into the wells of the wheels of parked cars. Once the moths mate, they die and the eggs manage to survive the harsh winter, according to Mass Audubon.

To prevent further spread of the gypsy moth outbreak, people are encouraged to be proactive and check their yards and cars for eggs during fall and winter months.

Within the next 2 weeks, the caterpillars will be reaching pupation, said Elkinton. Soon, those caterpillars that were affected by the spread of entomophaga maimaiga will be seen dead and those that survived become pupae and eventually moths who will reproduce and repeat the cycle.

Some people may have gypsy moth allergies. The Mass Audubon suggests these people wear gloves when dealing with the removal of them as eggs or when they become caterpillars.

According to UMass Amherst’s Center for Agriculture, Food and the Environment, the gypsy moth was brought to Medford from France around 1886 by Etienne Leopold Trouvelot who intended to use them to produce silk.

A few larvae escaped and thus began the infestation of gypsy moth caterpillars in 1889.

Gypsy moths contribute largely to deforestation by eating away at trees and leaves from the time they are caterpillars.

According to the Massachusetts Department of Conservation and Recreation, gypsy moths contributed to 350,000 acres of defoliation throughout Massachusetts in 2016 and are mainly attracted to apple, oak and willow trees.